Why Does My Dog or Cat Scratch So Much?

This very common client question unfortunately often has a complex answer, depending upon the individual pet. The first lesson in veterinary dermatology that we learned in veterinary school is to do a skin scraping, looking for scabies or demodex mange mites (more commonly seen in dogs), as well as taking scrapings for overgrowth of yeast or fungi like ringworm.

If these tests are negative the most common cause of scratching is often termed “allergies.” The three broadest causes of these allergies in dogs and cats, include flea bite allergies, inhalant/contact allergies to molds, grasses, trees, dander, house dust mites, pollens, and food allergies.  Some pets can have multiple factors from these three major groups. These frustrating itchy dogs and itchy cats can often develop secondary bacterial or yeast infections, which must also be addressed if the scratching is to be resolved. Often secondary oral antibiotics or antifungal medications are needed, which can be determined by a veterinary exam and the above testing. In middle aged and older pets, we will sometimes see hormonal disorders as contributing to skin infections and itchy pets.  So, sometimes thyroid and adrenal gland function testing are indicated depending upon the individual pet’s presentation.

Is your cat constantly scratching? One of the first things a veterinarian may do for a very itchy dog is to sometimes treat for hidden scabies mites (which do not often show up on skin scrape) with products like Ivermectin or Revolution, as well as change a pet to a low allergy, novel protein prescription diet for a minimum of a few months. In addition, a veterinarian may treat the secondary bacterial or yeast infections from all of the itching with appropriate antimicrobials and specific shampoos, such as Ketochlor, Oxydex, or Chlorhexidine Shampoo; especially in pets with secondary infections contributing to the scratching. For cats, a low allergy diet is often tried as well.

If there is not adequate improvement in the itching, then veterinary dermatologists will often perform blood and/or skin allergy testing to find out what a pet is allergic to, so that appropriate allergy treatment can be formulated. If a client goes through an entire dermatology workup, costs can climb quickly, especially with the allergy testing and recheck exams, as often up to one year of allergy vaccines are tried before deeming treatment a success or failure.  Average success rates for inhalant/contact allergy dogs and cats (also known as atopic dogs/cats) can range from 60 to 70 percent. For the remainder of the patients, and for those animal guardians who do not go for a complete dermatology workup, symptomatic management with various antihistamines like Diphenhydramine, Chlorpheniramine, and Clemastine can be tried.  When combined with excellent Omega 3 fatty acids like Be Well, Super Omega 3, or Missing Link for Dogs and Missing Link for Cats, and appropriate shampoo therapy, symptoms can often be controlled, but are difficult to cure.

Prescription  allergy pet meds like Atopica and Prednisone are needed for extremely itchy, nonresponding pets. Natural supplements like Proanthozone, DMG liquid, or Yucca Intensive may also offer effective alternatives in itchy pets.  I find that no one protocol works best in all pets, and that various combinations from the above groups and various therapeutic trials are needed to find the right combination that works best in a given pet. In addition, all itchy pets should be on some sort of flea preventative product, whether conventional Advantage or Frontline Plus, or natural flea and tick products to eliminate the always potential possibility of flea bite allergies involved.

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  1. Now that you mention it, I don’t know why I’ve never thought that my dogs scratching could have been caused by allergies. Reckon I will have to keep that in mind next time he starts scratching again.

  2. It’s not about my cat scratching himself. He scatches the hell out of me! He’s only 3 months old aswell.

  3. I have been giving daisy over the counter bendryl 325mg for allergy . My vet (recently retired) told me it was OK to give it to her. I have been giving it to her with her food.
    Am I doing the right thing??
    Her allergy is almost an on going thing.

  4. Dr. Michael Dym, VMD veterinarianMay 7, 2010 at 11:59 pm

    Benadryl or diphenhydramine is fine to give for allergies. A dose of 325 mg does not sound correct, however. The typical dose in dogs is one half to 1 mg per pound twice daily. Thus a 25 pound dog may get up to 25 mg benadryl. Sometimes other antihistamines such as chlorphenirimine or clemastine can help especially if any of these are combined with an omega 3 fatty acid supplement. Also I will often use antioxidants like proanthozone, as well as DMG liquid in addition to yucca intensive, all which can sometimes help in allergic pets.

  5. Thank you for Posting & I got to read nice information on your site.

  6. Dr. Michael Dym, VMD veterinarianJune 11, 2010 at 11:44 pm

    You are very welcome. Please tell all of your family and friends.

  7. Thank you for Posting & I got to read nice information on your site.

  8. Dr. Michael Dym, VMD veterinarianJune 13, 2010 at 7:14 pm

    Thanks for compliments. Please pass information about this service on to your friends and family

  9. Adopted a 7 week old lab/beagle mix (so the SPCA) said about a week ago, puppy was caged the entire time in the SPCA. After we got her home we noticed itching and a rash on her belly. Took her to the vet 2 days after we got her, the prescribed Clavamox, benadryl and some shampoo for sensitive skin. Now about a week later she is still itching but the rash is gone, chews on her paws a lot too. Immediately they want to do allergy testing, should we change to a good dog food and supplements first with an antihistamine to control the itching along with regular baths before we spend all the money on the testing?

  10. Dr. Michael Dym, VMD veterinarianNovember 13, 2010 at 11:53 am

    I would not rush into allergy testing. If dog is intensely itching may want to ask vet about skin scraping for hidden scabies and even treatind for it as it is hard to find on skin scrape. I would also try a low allergy natural diet like rabbit or venison, etc. 1800petmeds has wonderful selection of new diets. Must give dietary trial at least 6-8 weeks. I do think that allergy testing a puppy at this age is a bit premature. Antihistamines can be used to help a bit in mean time while you do diet trial and/or assess for scabies.

  11. We got our cat a super scratcher cat pad for Christmas. He loved it he would lay on it sleep on it etc. Since then he has been scratching and nawing himself crazy. Do you think this is because there is cat nip in his hair or could it be something else? He has never scratched himself like this before. He is an inside cat so I don’t think it’s fleas. He is also a Himalayin so he is a long haired cat.

  12. Dr. Michael Dym, VMD veterinarianJanuary 8, 2013 at 6:46 pm

    Could be inhalent/contact allergies, food allergies or nervous hair pulling/itching. Best to have vet check to sort out. You could try chlorphenirimine at dose of 2 mg twice daily as antihistamine as well as oral fatty acid such as missing link from 1800petmeds.

  13. Can I post a reply here?…

  14. Dr. Michael Dym, VMD veterinarianJuly 13, 2013 at 5:56 am

    Please do not advertise your products on this forum.

  15. My dog sassy (she is a Yorky) scratches all the time . We use oatmeal shampoo for bathing .
    I have tried several different sprays but nothing works. I cant a ford to take her to the vet . we keep up on all her shots. her food i went to puppy to adult back to puppy with the vet said it
    would be good to switch her back . what can i due next Thank You Cynthia Pulsifer

  16. Dr. Michael Dym, VMD veterinarianSeptember 2, 2013 at 9:53 pm

    Try antihistamine such as chlorphenirimine at dose of 2 mg twice daily. Also can try yucca intensive from 1800petmeds. Also add fatty acid to meals such as be well which can help when used long term.

  17. I want to know can dog use essentail tea tree oil with mixed with any shampoo bec she has itchy and smell odor body of skins but is danger to use essential tea tree for dog?

  18. Dr. Michael Dym, VMD veterinarianSeptember 9, 2013 at 11:33 pm

    Diluted essential tea tree oil is fine, however some dogs are very sensitive to this and need to be watched for any reactions.

  19. I have a calico cat,she is 13yrs old.she is costantly scraching,she also has scabs all over her body,could this be some kind of allergy,or would it be something more serious? I have taken her to the vet and they give her a shot that seems to help but does not last for very long.Any suggestions?

  20. Dr. Michael Dym, VMD veterinarianSeptember 26, 2013 at 12:10 am

    Most likely allergies. Make sure on good flea control product like topical revolution from 1800petmeds. Also consider antihistamine like chlorphenirimine at dose of 2 mg twice daily and add fatty acid like be well to meals from 1800petmeds. See vet for allergy workup if persists.

  21. Thank you for the info will try

  22. I am writing you back because what you have suggested and that is not working. Still looking for something to help . I would like any other suggestions you may have.Again thank you for your time.
    Cynthia Pulsifer

  23. Dr. Michael Dym, VMD veterinarianOctober 14, 2013 at 11:14 am

    HI Cynthia. Can you let me know details of your situation again and what you have tried.

  24. Have an Abyssinian cat about 5 years old, been havering repeated scratching, about twice a year. For last 3 years. Vet put her on Prednisolone and Entederm ointment to apply to lesion.
    Is there any alternative natural product I can use.
    Please advise.
    Thank you.

  25. Dr. Michael Dym, VMD veterinarianFebruary 6, 2014 at 12:54 am

    Try yucca intensive by azmira from 1800petmeds. also use proanthozone antioxidant, as well as can add fatty acid like be well to meals.

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